fix coverage in noHighlighting function

Author: Mia-jeong

lib/mocha.js

@@ -690,9 +690,9 @@ Mocha.prototype.noHighlighting = function(enableHighlight) {
   utils.deprecate(
     'noHighlighting is deprecated; provide {reporterOption: {highlight: false}} to mocha.setup().'
   );
-  enableHighlight = enableHighlight === undefined ? true : enableHighlight;
   this.options.reporterOptions = this.options.reporterOptions || {};
-  this.options.reporterOptions.highlight = enableHighlight !== true;
+  this.options.reporterOptions.highlight =
+    enableHighlight !== undefined && enableHighlight !== true;
   return this;
 };
 

test/unit/mocha.spec.js

@@ -300,6 +300,28 @@ describe('Mocha', function() {
       );
     });
 
+    it('should set the reporterOptions.highlight to false', function() {
+      var mocha = new Mocha(opts);
+      mocha.noHighlighting(true);
+      expect(
+        mocha.options.reporterOptions,
+        'to have property',
+        'highlight',
+        false
+      );
+    });
+
+    it('should set the reporterOptions.highlight to true', function() {
+      var mocha = new Mocha(opts);
+      mocha.noHighlighting(false);
+      expect(
+        mocha.options.reporterOptions,
+        'to have property',
+        'highlight',
+        true
+      );
+    });
+
     it('should be chainable', function() {
       var mocha = new Mocha(opts);
       expect(mocha.noHighlighting(), 'to be', mocha);